GastroEsophageal Reflux Disease (GERD) is a common medical condition that affects approximately 44% of the US adult population to some degree. GERD symptoms are currently the most common reason that patients visit a gastroenterologist. The lower esophageal sphincter is a one-way valve that normally prevents stomach acids from entering the esophagus. Failure of the lower esophageal sphincter allows stomach acid to reflux upwards into the lower esophagus, typically after meals when the stomach is full and exerts greater pressure on the lower esophageal sphincter. Strong stomach acids will burn the delicate lining of the esophagus, causing “heartburn” or “acid indigestion” to occur. Heartburn is experienced as a burning or pressure sensation behind the breastbone, and can be accompanied by foul-tasting regurgitation into the back of the throat. Recurrent heartburn will damage the esophagus over time, and can lead to more serious conditions, including a cancer of the esophagus known as “Adenocarcinoma of the Gastroesophageal Cardia”. Incidence of this particular type of cancer is rising in America and elsewhere.
Around 65 million Americans experience heartburn on a regular basis. The symptoms are uncomfortable, and most will seek some form of treatment. Options for treatment of acid reflux range from over-the-counter remedies and behavior modification (such as sitting up after meals or avoiding certain foods) to prescription drugs and surgery. Medications treat the symptoms of GERD, but do nothing to remedy the underlying cause. Drug treatments function by shielding the esophageal tissues for a period of time, stimulating their healing, or by suppressing stomach acid formation. All produce temporary effects and must be consumed on a regular basis. If the drugs are not taken, symptoms will very likely reoccur.
Surgical treatments are usually effective at eliminating the cause of acid reflux, and can be either open-incision or endoscopic (minimally invasive). The surgical procedure is designed to create a new functional lower esophageal sphincter or repair the damaged lower esophageal sphincter and thus prevent GERD. The most common surgical solution is to perform some variation of a procedure named “fundoplication”. This surgery involves wrapping the fundus (upper body) of the stomach around the lower esophagus, which causes compression of the lower esophagus when the stomach is loaded with food. This effectively prevents acid reflux. The wrap of the fundus around the esophagus may be 360 degrees or less. More complete wraps are associated with inability or difficulty in belching or vomiting. Partial fundoplications are therefore the preferred variation of this surgery. Fundoplications may be performed in an open procedure, or using an endoscope with a percutaneous approach (inserting the endoscope through one or more incisions in the abdomen).
Very recently, trans-oral endoscopic procedures have been developed for surgical treatment of GERD. One procedure involves constricting the lower esophageal sphincter by suturing. Another procedure involves constricting the sphincter by injecting a material into the surrounding tissues to “fatten them up”. Yet another procedure involves applying sufficient heat to surrounding tissues to stiffen them.
In copending International patent application PCT/IL01/00238 by the same applicant hereof, the description of which is incorporated herein by reference, there is described an endoscopic apparatus and procedure for performing partial fundoplications that provides an alternative to all of the above-mentioned options for the treatment of GERD.
Endoscopy is a mature class of surgery that came into wide use after the invention of the Hopkins “rod-lens” relay system in the 1960s. Prior to this breakthrough, endoscopes provided very poor image quality coupled with an inability to provide and transmit adequate illumination and were not suitable for most surgical and diagnostic applications. An endoscope is an optical instrument used to visualize the interior of the human body, through natural or surgical openings. The advantages of endoscopic procedures include less trauma to the patient, shorter (or no) hospital stay, less pain, faster healing, and generally lower cost per procedure. The advantages of open surgery include greater ability for the physician to see and manipulate structures. The earliest endoscopes relied on the physician to directly view the interior surgical site by looking through the eyepiece of the endoscope. As video camera technology evolved, endoscopes could be coupled to a video camera indirectly through a coupling lens attached to the eyepiece, or directly by coupling the image to the sensor without use of an eyepiece at all. The use of video displays allows the entire operating team to view the surgical site, and the surgeon is not required to keep his eye at the endoscope ocular. The use of video also permits documentation (image storage) without the use of bulky and inconvenient photographic equipment.
Endoscopes currently exist in an array of different forms and are suitable for a wide variety of surgical procedures. Most endoscopes are designed to provide a broad view of the interior surgical site, but do not necessarily provide adequate visualization of the tools used with the endoscope. Even though endoscopes may be highly specialized for a particular procedure, they all contain the same basic component systems. An objective optical system captures a single image or view of the surgical area, a relay optical system carries the image from the distal to proximal end of the device, and an eyepiece or camera system (or both) are used to view the transmitted image. Light to illuminate the surgical scene is delivered via optical fibers or waveguides that are integral to the endoscope. The endoscope may also contain working channels or incorporate treatment options such as laser delivery. All of these parts are contained within an outer sheath that may be made from rigid or flexible materials. The endoscope itself may be rigid, semi-flexible, or flexible, and may have the ability to actively bend in one or more directions at its distal tip.
The objective of an endoscope may consist of glass or plastic lenses, diffractive or hybrid diffractive/refractive lenses, GRIN (graduated refractive index) lenses, prisms or mirrors. The image relay system may consist of a series of glass rods and lenses (a “rod lens” system), a series of lenses only, or fiberoptic image guides. The relay system may be bypassed in a video-only endoscope by placing the image sensor directly in the objective focal plane. The eyepiece typically consists of glass or plastic lenses. A video camera may be coupled to the eyepiece via a coupling lens, or may connect directly to the endoscope and view the image formed by the relay or objective system directly. A light source is coupled to the endoscope by a flexible fiberoptic cable in most cases, and is delivered by optical waveguides or fibers that may be glass or plastic. Some endoscopes provide viewing in stereo by incorporating more than one optical system at the proximal end to view the scene from two slightly offset perspectives. While these stereo endoscopes incorporate multiple image channels, they provide only one view of the surgical scene on an electronic display.
Endoscopes may be reusable or disposable, or may be split into one or more disposable and one or more reusable parts. Advantages of reusable endoscopes are that they are usually of much higher quality and have durability designed in. Disadvantages include degradation of the image quality after sterilization, which is performed using such methods as steam autoclave, ETO (ethylene oxide), glutaraldehyde, Steris (peractic acid), Sterrad (hydrogen peroxide plasma), or other harsh chemicals and temperatures. The sterilization process degrades optical coatings, cements, and surfaces, and can also have deleterious effects on the mechanical parts. Another disadvantage of reusable endoscopes is their comparatively high initial cost. Disposable endoscopes do not suffer from repeated sterilization, and also reduce the possibility of cross-contamination from one surgical procedure to the next. Because they must be purchased in larger quantities and do not need to be as durable, initial costs are less than reusables (though per-use costs are typically higher). Endoscopes that are partly disposable and partly reusable are designed to maximize the advantages of each type of device while minimizing the disadvantages and cost per use.